Enrichment of Plasticicumulans acidivorans at pilot-scale for PHA production on industrial wastewater

A PHA producing microbial culture dominated by Plasticicumulans acidivorans was enriched in a pilot plant using fermented wastewater from the Mars candy bar factory. The pilot plant comprised (1) anaerobic fermentation, (2) enrichment of a PHA-producing microbial community and (3) accumulation for maximization of the cellular PHA content. After anaerobic fermentation, the wastewater contained mainly VFAs (0.64 ± 0.15 gCOD/gCOD) and ethanol (0.22 ± 0.13 gCOD/gCOD). In the enrichment reactor (cycle 12 h, SRT 24 h) a feast-famine pattern was established with a feast phase of around 35 ± 5 min. The culture was able to accumulate 0.70 ± 0.05 gPHA/gVSS. The difference with previous lab-scale results from P. acidivorans, in which a PHA content of 0.90 gPHA/gVSS was achieved, could be attributed to the presence of solids in the influent, the growth of a side population and the accumulation of non-PHA storage compounds that appeared to be related to ethanol consumption.